Well perforator firing means



Feb 9g 1960 J. J. ROBERTSON 2,924,173

WELL PERFORATOR FIRING MEANS Filed June 19. 1956 Jal/N J. oerso/V INVENTOR.

By wfg/M United States Patent O WELL PERFORATOR FIRING MEANS John J. Robertson, Fort Worth, Tex., assignor, by mesne assignments, to Welex, Inc., Fort Worth, Tex., a corporation of Delaware Application June 19, 1956, Serial No. 592,411

Claims. (Cl. 102-20) This invention relates to well perforating means and more particularly to means for controlling the ring of the perforating means upon positioning thereof in a well. It has been the practice in the completion of wells such as oil and gas wells drilled by the rotary method to perforate the well casing adjacent the producing formation to admit oil and gas from the formation to the well. This perforation has been accomplished with the drilling mud in the casing and before the well was capped. -It has become the practice more recently -to perforate after the tubing has been inserted into the well, the well head equipment axed andthe 'drilling mud removed. This latter method requires lowering through the relatively'small tubing-the perforating assembly to the vicinity of the' producing formation and then perforating. l

In lowering an assembly through such tubing it is desirable to maintain the perforating units in vertical alignment permitting the units to pivot upon emergence from the tubing to a horizontal firing position. Such an assembly is disclosed in W. H. Thompson et al. patent No. 2,543,814, issued March 6, 1951, on- Means and Method of Tilting Explosive Charges.` An improvement on this type of assembly which provides for the retraction of the assembly after emergence from the tubing is described in an application for United States Letters Patent -led February 19, 1954, by Blake M. Caldwell and loe P. Wier, Serial No. 411,349, entitled Tilting Charge Well Perforating Assembly. A further improvement upon such an apparatus resides in controlling the pivoting of the perforating units from the ground surface and also in guarding against unexpected tiring of the units as described in an application for United States Letters Patent filed October 8, 1954, by Blake M. Caldwell and Harrold D. Owen, Serial No. 461,236, entitled Well Perforating Assembly. It is with improvements in the apparatus disclosed in this latter application that the instant invention is particularly concerned. i

In such an apparatus there is provided a ring head having an elongated carrier suspended therefrom. A plurality of pivotally mounted perforating units are mounted in the carrier biased towards a horizontal position but interlocked in a vertical position. Means are provided to release the interlock to permit pivoting of the units, and such latter mentioned means are actuated from the surface. As set forth in the latter mentioned application, the firing circuit for the individual perforating units cannot be completed until the interlock has been released and the units pivoted to their tiring positions. Y l

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It is, therefore, an Vobject of this invention to provide means preventing tiring of the perforating units unless pivoted to the firing position.

Itis a further object of this invention to provide means which in one position permit release of the interlocked perforating units and which after release of the units permit ring thereof.

It is still a further object of this invention to provide means whereby foreign matter encountered during lowering of the assembly into the well cannot aiect the operation thereof to release the interlocked perforating units or permit tiring thereof.

Other objects and advantages of this invention will be readily apparent from the following description:

In the drawings:

Figure l is a side elevation of -avperforating assembly embodying this invention having portions thereof broken away.

Figure 2 is a fragmentary view similar to Figure 1 lafter release of the perforating units.

Figure 3 is a schematic wiring diagram.

The perforating assembly generally comprises a firing head 10, supported from the surface by a conductor cable (not shown). An elongated carrier 12 is mounted upon and suspended from the tiring head and has a iiring fuse 14 threaded therethrough passing adjacent to the perforating units, in this instance, shaped charges 16. The charges are pivotally mounted within the carrier 12 as by pins 18 and each is biased to a horizontal position by a springl 20. During descent through the tubing of the well, however, the charges 16 are locked in axial disposition with respect to said carrier 12 by means of interlocking detents 22 and 32'. A blasting cap 24 engages the lower detent 32 on the lowermost shaped charge 16, which cap is exploded from the surface of the well permitting spring 20 to pivot the bottom shaped charge to a horizontal position. This pivoting breaks the interconnection between detents 22 on upper end of the bottom shaped charge and 32 on lower end of the charge immediately above permitting similar pivoting thereof, thereby successively freeing each charge 16 in the carrier 12 to pivot to its firing position.

The above description of the device is believed adequate for the present application, but a more detailed description may be found in the above-mentioned United States patent application Serial No. 461,236. In. any event, the instant invention is directed to means employed for completing the circuit for ring cap 24 permitting pivoting of the charges 16 to the ring position whereby said means arms the firing circuit for the shaped charges.

In general the invention involves an element inserted into the carrier and axially aligned therein by engagement with the shaped charge immediately below which element contains means for completing the circuit permitting release of the shapedcharges to pivot to the ring position. The element upon release likewise pivots to a firing position thereby arming the shaped charge firing circuit.

The arming element 26 has an exterior shape similar to that of the shaped charge 15 and is pivotally mounted in the carrier by pins such as 28 and a spring 30 biases the arming element to a substantially horizontal tiring position. The arming element 26 at its lowermost extremity has a detent 32 which interlocks with detent 22 on the upper extremity of the next lower shaped charge 16 in the carrier. Thus the arming element 26 1s substituted for the top shaped charge in the carrier and pivots to yan arming position as do the remaining shaped charges 16 upon exploding of cap 24.

The arming element 26 has a central chamber 34 containing a mercury switch generally designated 36 rigidly secured therein. The switch comprises an upper chamber 38 and a lower chamber 40 with a restricted throat 42 therebetween which eliminates accidental splashing of the mercury 44 during lowering of the assembly into a well.

During descent of the perforating assembly into a well the arming element 26 is in axial alignment with respect to carrier 12 and the mercury 44 is in lower chamber 40 of the switch completing an electrical circuit between contacts 46 and 48 which are spaced from one another and project through the electrically non-conductive shell of the switch 36 into chamber 40. Upon firing of cap 24 from the surface of the well and release of the interlocked charges the arming element 26 is pivoted to substantially a horizontal position whereby the mercury flows from chamber 40 into chamber 38 completing the electrical circuit between contacts 50 and 52 which are spaced from one another and proiect into chamber 38. To facilitate the flow of mercury from chamber 40 to chamber 38 the shell of switch 36 that is the longitudinal axis through the chambers 38 and 40 may be inclined to the vertical in the direction of pivoting of the arming element 26 a slight amount.

The contacts 46 and 52 are interconnected by wires 54 and 56 which at their union are fixed to wire 58 which at the surface of the well is connected to a suitable source of electrical power. The contact 48 s connected bv wire 60 to can 24 which can is suitably grounded to the carrier while contact S is connected by wire 62 to an electricallv operated blasting cap 64 which is likewise suitablv grounded to the carrier.

Thus when the arming element is in the axially aligned position in thecarrier the circuit through contacts 46 and 48 is completed to can 24 which may-then be fired bv energizing the circuit from the well surface which as heretofore described permits successive pivoting of the shaped charges 16 and ultimatelv of the arming element 26. If the arming element should engage an obstruction in the well it will not pivot and conseduently the mercury 44 would not flow into chamber 38 to complete the circuit between contacts 50 and 52, thereby preventing firing of the shaped charges. lf the arming element does pivot to the firing position of Figure 2, i.e., the well bore is free of obstructions, then the mercury 44 Hows into chamber 38 completing the firing circuit. A further electrical impulse will, under these conditions. fire cap 64, this in turn fires detonator 66 housed in firing head 10 which in turn fires the tiring fuse 14 which sets oli the shaped charges 16.

To protect the wire leads and the mercury switch from well fluids the wires 58. 60 and 62 pass through a plastic head 68 secured in a suitable bore in the arming element 26 and are held therein by gland 70 preventing the well fluids entering the arming element 26. Similarly, wires 53 and 62 pass through a plastic sealing head 72 fitted within a bore in firing head and secured therein by a gland 74 preventing well iiuids entry into the tiring head 10.

Thus the arming element 26 is interlocked with the shaped charges 16 during lowering of the perforating assembly into the well and in this position completes an electrical circuit which may be energized to fire cap 24, permitting pivoting of the shaped charges and the arming element to the firing position wherein the arming element completes the firing circuit which may then be energized to fire the shaped charges.

While what hereinbefore has been 'described is the preferred embodiment of this invention, it is readily appar- 4 ent that alterations and modifications can be resorted to without departing from the scope of this invention and such alterations and modifications are intended to be included within the scope of the appended claims.

I claim:

l. A well perforating assembly comprising; an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an explosive member maintaining said elements in an interlocked relationship; an explosive member firing circuit; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements; said arming member including a switch being entirely a part of said arming member for completing the circuit to said explosive member while said arming member is in axial alignment with said carrier, whereby current may be caused to flow through said completed circuit to lire said explosive member to release said elements from interlocked relationship.

2. A well perforating assembly comprising; an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an explosive member maintaining said elements in an interlocked relationship; an explosive member tiring circuit; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements; said arming member including a switch being entirely a part of s..id arming member for completing the circuit to said explosive member while said arming member is in axial alignment with said carrier, whereby current may be caused to ow through said completed circuit to fire said explosive member to release said elements from interlocked relationship; and a shaped charge firing circuit; said switch completing said shaped charge tiring circuit when said arming member is pivoted out of axial alignment with said carrier.

3. A well perforating assembly comprising; an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an explosive` member maintaining said elements in an interlocked relationship; and explosive member tiring circuit; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements; said arming member containing a pair of spaced contacts forming elements of said explosive member firing circuit and an electrically conductive uid therein which when said arming member is in axial alignment with said carrier flows to a position bridging said contacts to complete said explosive member firing circuit.

4. A well perforating assembly comprising; an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an explosive member maintaining said elements in an interlocked relationship; an explosive member tiring circuit; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements; said arming member containing a pair of spaced contacts forming elements of said explosive member tiring circuit and an electrically conductive uid therein which when said arming member is in axia l alignment with said carrier ows to a position bridging said contacts to complte said explosive member liring circuit; and a shaped charge firing circuit ncluding a second pair of spaced contacts in said arming member; said electrically conductive tluid ilowing in said arming member to a position bridging said second pair of contacts to complete said shaped charge firing circuit upon pivoting from the axially aligned position with respect to said carrier of said arming member.

5. A well perforating assembly comprising; an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an explosive member maintaining said elements in an interlocked relationship; an explosive member tiring circuit; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements;'said arming member having a pair of interconnected chambers therein; a first pair of spaced contacts in one of said chambers forming elements of said explosive member firing circuit; an electrically conductive fluid partially llling said one chamber when said arming member is axially aligned with respect to said carrier and bridging said rst pair of spaced contacts thereby completing said explosive member ring circuit; and a shaped charge firing circuit including a second pair of spaced contacts in the remaining one of said chambers; said electrically conductive iiuid owing into the remaining chamber upon pivoting of said arming element and bridging said second pair of spaced contacts to complete said shaped charge tiring circuit.

6. A well perforating assembly comprising; an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an explosive member maintaining said elements in an interlocked relationship; an explosive member firing circuit; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements; said arming member having a pair of interconnected chambers therein; a rst pair of spaced contacts in one of said chambers forming elements of said explosive member tiring circuit; an electrically conductive iluid partially lling said one chamber when said arming member is axially aligned with respect to said carrier and bridging said first pair of spaced contacts thereby completing said explosive member liring circuit; a shaped charge ring circuit including a second pair of spaced contacts in the remaining one of said chambers; said electrically conductive uid llowing into the remaining chamber upon pivoting of said arming element and bridging said second pair of spaced contacts to complete said shaped charge tiring circuit; and a restricted throat between said chambers.

7. A well perforating assembly comprising; an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an explosive member maintaining said elements in an interlocked relationship; an explosive member firing circuit; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements; said arming member having a pair of interconnected chambers therein; a first pair of spaced contacts in one of said chambers forming elements of said explosive member firing circuit; and electrically conductive lluid partially lling said one chamber when said arming member is axially aligned with respect to said carrier and bridging said irst pair of spaced contacts thereby completing said explosive member firing circuit; and a shaped charge firing circuit including a second pair of spaced contacts in the remaining one of said chambers; said electrically conductive iluid flowing into the remaining chamber upon pivoting of said arming element and bridging said second pair of spaced contacts to complete said shaped charge liring circuit; the longitudinal axis through the chambers being inclined in the direction of pivoting with respect to the longitudinal axis of the carrier.

8. A well perforating assembly comprising; an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an explosive member maintaining said elements in an interlocked relationship; an explosive member liring circuit; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements; said arming member having a pair of interconnected chambers therein; a first pair of spaced contacts in one of said chambers forming elements of said explosive member firing circuit; an electrically conductive lluid partially lling said one chamber when said arming member is axially aligned with respect to said carrier and bridging said rst pair of spaced contacts thereby completing said explosive member tiring circuit; a shaped charge ring circuit including a second pair of spaced contacts in the remaining one of said chambers; said electrically conductive lluid owing into the remaining chamber upon pivoting of said arming element and bridging said second pair of shaped contacts to complete said shaped charge firing circuit; the longitudinal axis through the chambers being inclined in the direction of pivoting with respect to the longitudinal axis of the carrier; and a restricted throat between said chambers.

9. A well perforating assembly comprising: an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which then interlocked maintain said shaped charges in axial alignment with said carrier; means releasably maintaining said elements in interlocked relationship; electrically operated means for tiring said shaped charges; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking elements; and electrical circuit means for energizing said electrically operated firing means including a switch being entirely a part of said arming member, said switch being open when said arming member is in axial alignment with said carrier and being operable to close in response to pivoting of said arming member out of axial alignment with said carrier.

10. A well perforating assembly comprising: an elongated carrier; a plurality of shaped charges pivotally mounted in said carrier and urged to pivot out of axial alignment with said carrier; interlocking elements on each shaped charge which when interlocked maintain said shaped charges in axial alignment with said carrier; an electrically operated explosive member maintaining said elements in interlocked relationship and adapted upon explosion to release said elements; electrically operated means for ring said shaped charges; an arming member in said elongated carrier urged to pivot out of axial alignment with said carrier and restrained against pivoting by engagement with one of the interlocking ele ments; and electrical circuit means for independently energizing said electrically operated explosive member and said electrically operated shaped charge firing means including switch means being entirely a part of said arming member, said switch means being constructed and arranged to provide a closed circuit to said explosive member and an open circuit to said shaped charge firing means when said arming member is in axial alignment with said carrier, said switch means being operable in response to pivoting of said arming member out of axial alignment with said carrier to open the circuit to said explosive member and to close the circuit to said shaped charge firing means. Y v

References Cited in the Iile of this patent UNITED STATES PATENTS Disclaimer and Dedication .-J 7m J. B05677550 2,924,173ING? MEANS, Pateiit l T XNVELL PERFORATOR F1R- Firzitxexdote. Q 1960. Disclaimer and dedication tiled Nov. 14, 1967, by the assignee, Halliburton Uompzmy.

Hereby disclaims and dedicates to the Public the terminal portion of the 6. 1 tl datent subsequent to` Dec. 31, 196 teun o eOlyoz'aZ Gazette March 5, 11968.] 

